1. Technical Field
The invention relates to automatic milking apparatus and, more particularly, to the teat cup shells that hold the milking liners. Specifically, the invention relates to a bottom-weighted teat cup shell having ergonomic features and features that improve the seal between the shell and the milking liner.
2. Background Information
A typical teat cup shell is indicated generally by the numeral 2 in FIGS. 1-4. Teat cup shells 2 are typically made from metal or plastic. When made from plastic, shell 2 may include a metal feature that increases the weight of shell 2 as disclosed in U.S. Pat. Nos. 4,393,811 and 3,099,246 so that the overall weight of shell 2 is sufficient to pull down on the teats during the milking process. These teat cup shells seek to move the weight to the top of the shell or to spread the weight over as much of the shell as possible.
Teat cup shell 2 holds the milking inflation 4 that receives the animal's teat during the milking process. Shell 2 cooperates with liner 4 to define a vacuum chamber 6 that is subjected to a pulsating vacuum source controlled by a pulsator 8 as shown in FIG. 4. The vacuum applied to chamber 6 controls the application of liner 4 to the teat thus making the seal between liner 4 and shell 2 important to an efficient milking process. These seals also function to keep contamination out of chamber 6 to prevent pulsator 8 from being contaminated. A continuous vacuum is applied to the bottom of milking liner 4 through a milk hose 10. Milk that is extracted from the teat is removed from liner 4 through milk hose 10. A claw 12 (FIG. 3) is used to apply a vacuum to four teat cup assemblies and to consolidate the milk into a common milk hose. FIG. 3 depicts four teat cup assemblies connected to the teats of an udder.
When the user attaches the teat cup assemblies to the teats, the user is supposed to support claw 12 with one hand while positioning the teat cup assemblies on the teats with the other hand. The user is supposed to insert each teat in a liner in an even configuration so that liner 4 applies even pressure to the teat during the milking process. A teats cup assembly that is not properly placed will decrease the efficiency of the milking process by tilting away from the udder. The process of properly positioning the teat cup assemblies on the teats is difficult when the weather is cold and when the shells are wet. The users desire shells that are easy to hold in one hand while placing them on the teats under the animal.